ABSTRACT The Graduate Program in Biophysical Sciences (BPHYS) trains students with backgrounds in the physical sciences to address biological problems using quantitative approaches, thereby strengthening the biomedical research workforce. Launched in 2007, BPHYS promotes the University of Chicago?s unique interdisciplinary research culture. Trainees with strong undergraduate physical science preparation are selected on the basis of their demonstrated desire to exploit the tools of the physical scientist to better understand, and to develop therapies for, biomedical issues. The hallmark of the BPHYS Program is dual-mentored research bridging the biological and physical sciences. The trainee is a full member of both mentors? laboratories and becomes adept at communicating across disciplinary boundaries. Our trainees receive training in both the biological and physical sciences through a combination of lab-based courses, didactic courses alongside students in traditional disciplinary programs, and program activities. Intense interdisciplinary didactic and practical training occurs through research on an innovative, student-designed, dual-mentored thesis project. To strengthen the training experience and expand the scope of the Program, we will introduce an open research challenge in this project period. The entering and senior students will craft a short collaborative research proposal for implementation in our Y1 Biological Research Immersion lab course. The BPHYS Program is in its 12th year and has graduated 23 trainees, 15 so far in the current budget period (2014-2019). The Program has been successful in recruiting URM students with 14% identifying as URM; all are funded by the training grant, representing 25% of the total appointees. In addition, 36% are women. Program trainees have published 120 papers, contributing to multiple fields within basic and biomedical science. Early program graduates are entering academia (two are Assistant Professors) and industry; other more recent graduates are currently in post-doctoral positions. Program mentors actively recruit (and compete for) our BPHYS students because they can forge new and lasting collaborations between groups. Due to this demand, we have increased the number of students who matriculate into the Program over the course of the project period, from ~5 per year to ~8 per year with no decrease in quality. Accordingly, this application requests 8 trainee slots, which will support half of the students in the Program in their first and second years.